Sub-level cutting tool



March 10,1959 G..KEE, JR 2,876,777

SUB -LEVEL CUTTING TOOL Filed July 11, 1955 Fi .3 H 7 1 /////////////S INVENTOR.

' 67R5 [55 J/e. BY DES JARDINS, ROBINSON & KEISER HIS ATTORNEYS United vStates Patent SUB-LEVEL CUTTING TOOL George Kees, Jr., Alexandria, Ky. Application July 11, 1955, Serial No. 521,147

13 Claims. (Cl. 128-304) This invention relates to a surgical cutting instrument, and more particularly to a sub-level cutting tool which is adapted to remove a limited amount of material on each stroke of the tool and to retain the fragments thus removed when the instrument is withdrawn. The improved instrument is also designed to afford protection against damage to structures surrounding the material which is being removed.

The cutting instrument hereinafter to be described is designed primarily for the removal of growths and masses from the spinal canal. These masses most commonly occur at the base of the patients neck and are generally constituted of hypertrophic masses which form on the posterior surfaces of the bodies of the vertebrae, or excrescencies of the cervical discs which are commonly referred to as herniated discs. These masses press against the spinal cord and the nerve roots and thereby produce complications of varying sorts depending upon the location of the mass and its point of application of pressure on the cord or nerve root. Since the masses lie beneath the spinal cord, it is a difiicult and hazardous task to effect their removal by the use of ordinary surgical tools having unprotected cutting edges. job to remove the fragments of material left in the spinal canal since these are usually beneath the cord where they are difficult to see and to remove.

Accordingly, it is an object of the present invention to provide a surgical instrument which is adapted to remove growths and masses from the interior walls of the spinal canal without endangering the integrity of the nerves or spinal cord lying adjacent thereto.

Another object of the invention is to provide a sub level cutting instrument which is designed to remove a limited amount of material on each stroke of the instrument.

Another object fo the invention is to provide a surgical cutting instrument having a shielded cutting edge and an opening formed in connection therewith for receiving the fragments of material removed by the instrument.

With these and other objects in view which will become apparent from the following description, the invention includes certain novel features of construction, the essential elements of which will be set forth in the appended claims, and a preferred form or embodiment of which will hereinafter-be describedwith reference to the drawings which accompany and form a part of this specification.

In the drawings:

Fig. l is a perspective view showing one form of my improved surgical cutting instrument.

Fig. 2 is a plan view of the bottom portion of the instrument shown in Fig. 1.

Fig. 3 is a cross-sectional view taken along the line 3-3 in Fig. 2.

Fig. 4 is a perspective view of a modified form of cutting instrument.

It is also a tedious 2 Fig. 5 is a plan view of the lower end of the instrument shown in Fig. 4.

Fig. 6 is a cross-sectional view taken along the line 6-6 in Fig. 5.

Fig. 7 is a view showing the manner in which my im proved form of cutting instrument may be used in the removal of masses from the anterior wall of the spinal canal.

Fig. 8 is a cross-sectional view illustrating more specifically the cutting action of the instrument.

As heretofore indicated, the present invention relates to a curette type of surgical instrument which is especially adapted for use in removing growths or hypertrophic masses as well as the excrescent material of herniated cervical discs from the interior wall of the spinal canal. In the drawings I have shown two forms of cutting instruments which embody the principal features of my invention, one of these forms being shown in Figs. 1, 2 and 3 and the other in Figs. 4, 5 and 6.

Referring first to the form of instrument shown in Figs. 1, 2 and 3, it will be observed that the instrument is in the form of a rod, preferably of hexagonal crosssection, which is comprised of high-grade surgical steel. The upper end of the rod constitutes a handle 10 which is of suflicient length to permit both hands of the user i to be applied thereto as shown in Fig. 7. Toward its lower end the handle is flattened to form a shank 11, which is curved at 12 to provide an upturned end on the instrument. The upturned end is provided with an opening 13 therein so as to provide an eye-shaped extremity 14 provided with a rounded end 15.

As best shown in Fig. 3, the forward wall 16 of the opening 13 forms one surface of a cutting edge 17, the

determined depth. Hence, as the instrument is drawn toward the user, an elongated fragment 19 will be removed by the cutting edge. The bottom surface of this fragment will be curved in the transverse direction as a result of the curvature of the cutting edge as shown in Fig. 2. After the fragment 19 has been removed, it will be retained within the opening 13 as the instrument is withdrawn to thereby carry the fragment out of the canal.

To effect proper cutting action by the edge 17 and to insure withdrawal of the fragments of material removed by the instrument, the forward face 16 of the opening should be inclined at an angle with respect to the bottom surface 18 of the instrument as indicated by the angle A shown in Fig. 3, this angle lying within the range of from 50 to 60 degrees for best cutting and chip removing action. Also, the length of the face 16 along the line x-x should be of sufficient length to accumulate and retain thereon the small fragments of material removed by the cutting edge.

It will be observed that in this instrument the cutting edge 17 is protected by the rounded nose 15 at the forward end of the extremity 14 so as to reduce the danger of damage to surrounding structures by the end of the instrument. the instrument, the removed fragments 19 may be emptied from the opening 13 so that very little clean-up workre mains to be done after the spur has been removed.

Patented -Mar. 10, 1959 After every stroke, or every few strokes, of

face of a curved cutting edge 30." The other surface of the cutting'edgeis provided-by-thebottom surface 31 of the extremity 27. As will be seen from Fig. 6, the cutting edge 30 projects slightly below the adjoining side suff'aceson"thebottom'of' the extremity so as to'produce Cit a sub-level cuttinginstrument which, when pushedacross the'material to be removed, will cut a fragment SZtherefrom. This fragment will be prevented from escaping 1 from the opening-28b) the forward edge 33 of the opening." In thistype of instrument, as in the form shown range of from to 30 degrees for best cutting action and the dirnension of the opening 28 in the fore to aft direction,.that is from the edge 33 to the face 29 should be less than the length of the face measured along the line y-y. This will insure that the accumulation of fragments 32 removed by the instrument will be retained within theopening 28 and thereby withdrawn from the canal when the instrument is removed.

The forward end of the extremity 27 is rounded as indicated by reference numeral 34 so as to provide .a curved guard for the cutting edge and thereby reduce the danger of damage to surrounding structures.

In Fig. 7 I have shown the manner in which the instrument may be used to enter beneath the spinal cord in the spinal canal and remove hypertropic masses or herniated disc material from the anterior wall of the canal. In a-like manner, offending material may be removed from beneath the nerve roots 41 where it presses against the nerve and causes discomfoitto the patient. This condition is illustrated in Fig. 8 in which spurs 43. formed on the vertebrae 43 are shown pressing on the nerve root 41. As will be seen from Fig. 8, the completely shielded cutting edge of the instrument minimizes the possibility of damage to the dura ofthe overlying nerve or of the adjacent spinal cord 40 so thatthe spurs 42 may be safely removed from the vertebrae.

While I have described my invention in connection with two possible forms thereof and have used, therefore, certain specific terms and language herein; it is to be understood that the present disclosure is illustrative rather than restrictive and thatchanges and modifications may;

be resorted to without departing from thespirit or the scopeof the claims which follow.

Having thus described my invention, what I claim as new and useful and desire to secure by United'Statcs Letters Patent, is:

1.: A surgical instrument comprising an elongated shank an upturned end on said shank formed with an opening therein to provide an eye-shaped extremity thereon-having acarvedbottom surface, a cutting edge on the; bottom-of said .extremity, one surface of said edge being formed'by the inner face of said opening and the other surface of'saidedge being formed by the bottom surface of said extremity, the bottom surface of said extremityoneachside of said cutting edge being elevated sufiiciently with respect to said cutting edge to cause thclatter to project downwardly below the level of the bottom surface of the extremity on each side thereof and thereby provide a sub-level cuttinginstrument adapted to cut below the levelof the curved bottom surface of said extremity a furrowofpredetermined depth ,inthe material to betremoved.

This

2. The surgical instrument of claim 1 wherein said cutting edge -is formed at the forward end of said openmg.

3. The surgical instrument of claim 2 wherein the distal end of said extremity is rounded to provide a curved guard on the end 'of said instrument.

4. The surgical instrument of claim 2 wherein said cutting edge is curved in a plane lying perpendicular to the direction of cutting so as to cause an arcuate furrow to be cut in the'material to be removed.

5. The cutting instrument of claim 2 wherein the inner face of said opening lying adjacent said cutting edge is inclined at-an angle of-from to degrees with respect to the bottom surface of said extremity on each side of said cutting edge and is longer in the direction of cutting than the dimension of the opening in the longitudinal direction whereby the fragments of material removed by the cutting edge will be retained in the opening as the instrument is withdrawn.

6.'Th'e surgical instrument-0f claim 1 wherein said cutting edge is formed at the rear end of said opening.

7. The surgical instrument of claim 6 wherein the distal end of said extremity is rounded to provide a curvedguard on the end of said instrument.

8. The surgical instrument of claim 6 cutting edge is curved in a plane lying perpendicular to the direction of cutting so as to cause an arcuate furrow to be cut in the material to be removed.

9. The surgical instrument of claim 6 wherein said inner face of said opening lying adjacent said cutting edge is inclined at an angle of from 20 to 30 degrees with respect to the bottom surface of said extremity on each side of said cutting edge and is longer in the direction of cutting than the dimension of the opening in the longitudinal direction whereby the fragments of material removed by 'the cutting edge will be retained in the opening as the instrument is withdrawn.

10. A- curette surgical instrument comprising an elongated shank having an upturned distal end on said shank formed with an opening therein to provide an eye-shaped extremity thereon having a curved bottom surface, and a transverse cutting edge on one edge of the opening projecting downwardly below the level of the bottom surface of the upturned edge to provide a sub level cutting portion adapted to out below the level of the curved bottom surface a furrow of predetermined depth in the materialto be removed.

ll. A curette surgical instrument comprising an elo-ngated shank, an upturned end on said shank formed with an opening therein to provide'an eye-shaped extremity thereon, and a cutting edgeon one-transverse end of the opening'formed by the inner face of said opening and the bottom face of said extremity, said cutting edge being transversely-curved downwardly'between opposite References Cited inthe file of this patent UNITED STATES PATENTS Kracht Apr. 8, 1924 Grover Sept. 5, 1950 MacLean Aug. 23, 1955 wherein said surgical instrument of claim 11 

